Activision sends news of plans to include cheat protection in a future patch for
Call of Duty:

We know concerns about cheating are a big issue in the fan
community right now, so we wanted to pass along the following update: Infinity
Ward has signed a deal with Even Balance to include PunkBuster for Call of Duty.
As more information, including timing, develops on releasing PB support for Call
of Duty, we'll let you know. Thanks!